SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c41f8043ec0b4facca6614a322350a52c94a5131f98e85a23b2e344f3aa73b4' 
  AND token = 'vDNcx8YU1TQONJaMt7djvVZekw1+aB+Ef5bujVDCyUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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