SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efd9241065662799bac79e196197339404b949efca0b6071b32a650d5486c6d5' 
  AND token = 'qXHM5PhHMePnEff5FSL9iC/HNeqzUzqDC9shOExTOy8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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