SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb9055844d55fcc27056fbabb9ecd59b077d10749bbf8abf94ad690c946aaae5' 
  AND token = 'UVud8fTGzwVxS9lc/0Hr35+1vgBwP4ier5xMJqNNVm4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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