SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92afa6a1c6ed5e1f6d7a4e20382938a7f8811e34ebe9313f43af3c369047ec0e' 
  AND token = '6h1vVcfW87aN+B2vy7xCJCC+jedtS2XT2IahPvYzuBE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}