SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6948bd74f69dbc7b792a0a919d21aae8db19e9fc9655846de0574f04045eb282' 
  AND token = 'saN5NuBA/7mqynZyn27NjgsY7iTBH4QJwMq8PhJLlWk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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