SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66b33734cbb52250c1f6ee82d6915f82cb04ddcfefc94bed14badda66f4834f2' 
  AND token = 'ksvW78j/mhammJY2awJhiZeJk8QkOwFpVqJ8RwTlQMA=' 
  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"
    }
  }
}