SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3494b3e1c669a3946546e22f113c422495531e5c62aefb035fa94dc7ba0b394b' 
  AND token = 'OnwozVfHNjxJ62aehi4vQyVEjm6l4PPOIlftCIhdm3A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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