SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a48882dfe7412c80867dbdaf8ca79ebc2dde0151f9ebd4c20a01f23f9d268bda' 
  AND token = 'xKFcCgOwnaGwgVP/MCg5ABehuWs7KODhrr1kgJp4280=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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