SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f02b71009558f3673d2c4b00954e343009a83f8fa85fcd35f66170a9ccadd62f' 
  AND token = 'K7oqEu4GiX8uWWDj1CADnShOfmtvjZ9aj+l4fI2XigY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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