SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39e83449b2f58868167de036ef9c65e05c750811542cb2c3bf2c9226b544f1de' 
  AND token = 'ZmpK+0caGhJqyLT8oinVTHiyZ/03VLKsZbpBr6YAyD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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