SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '632a854f29f5406357e8239fdcb5247b83ac1c5739dba92b492b2c76177d81a3' 
  AND token = 'NCch18dLGWXdoG+sJnnnr0RMn4yKK7pI4jm6XeyaOEc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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