SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53f3b3597ea7f440871308301232a28d9aa56a21db03817fd23b58206a0c5df2' 
  AND token = 'zUAwtPsZkNnJHCfgzF1/5bzrSi3xRmz6i215KtPcKjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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