SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f294c269911480364289a4ae93041d937345302d162e634d846d9241413c81b2' 
  AND token = 'N4FwaFm+HVfvPXwisyWDdYZhW8UMBThfgf3D3ZdSGU8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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