SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae75fb19cea15ca4845919bf3248daefbcb1c3bce25411ec2dc0c43ba60bf31b' 
  AND token = 'N6NfkhGrXRRbOVACAvXRgJB1Ovq4nUwi4Yu4Njilg7U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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