SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1c9628c519d3bfa5059b353b9376aa11b231332e660e3e1df45a4f01351d6a6' 
  AND token = 'KJpQIbBNALUsqQCB+WZ2E0y+RXWFqvHxlVZjFCrJKbA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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