SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc047fadbe1ff8a084f9c875ddb00e63b214437e3817e27d1365e74eb5554a49' 
  AND token = 'KH9tebMtnMoHXCAGRe6V2aoRlSSTnmaThpGpcM1FRO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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