SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cae2e3280c159eb184147075902989a64b961b9ed77a219075e0b1dc9af87b9' 
  AND token = 'lMGuwZiPmqKNNAjHwMR5RXIPDmc9Jnkz/OhxQrkgv8A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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