SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eaec06a81be43c771adb244d00d1a23ab81485e83d6fdbdf9bacf2b65caef775' 
  AND token = 'UZmjY+J2cAhkqzabFQzafBjK3VJ/lwAVXK3Omhv/fEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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