SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '294b96139f7e89b135cc950706301676243a374e91bc5bdd4ec19874fe2d6b3d' 
  AND token = 'ZGrx6NqeBNSLlfV58gm2txZjxpVvhpFNO6sox3xvd7M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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