SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9bbad5775af05a6a800ecc442ba2ea278ac74a21a9d105f27132439ddf0413c' 
  AND token = 'ggMEnPKbZAWRruCOuMGdT1LjIKy/Gx6iL8AHOrALwQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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