SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42731db9ba9f49ebbc5460247d0de1024e7287b71e60d0a18e612dc845444920' 
  AND token = 'a2dKj91wi8oIzCQAZG5aeDfBvoUPiDBBLE+jYg57efk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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