SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b736a4742371c39fa71b6bc856599dc4110dc2fa439f5f21665dce7c64a86243' 
  AND token = 'c0KNGtebKwdmE+fUuRMveAO+vKKOUyhPJ9YrrqY7VIo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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