SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2075602d968477e245dccd317b4699ccffffa27252cf92bcf77b493de75b6dc3' 
  AND token = 'OQzHPoDzdzbutD51mx5j4UBwrtp1KCc7vUOFVxn58SY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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