SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52b81e304962cacd7594b1ee3c3a1a5370e449f9694c3f136bfb851f621d0e55' 
  AND token = 'E17xXx++J38Y2erUwhzqXVgy+ZdT1H+ztSxU6vNZ7js=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}