SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0cbb37f6454c5e07c9672839a377669442f09e9cdd916c3d85d7fcc62014ad2e' 
  AND token = 'LDCsjqLp+JFrgImjAWmZhu03pGS/4f2qA/qL/ChDY18=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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