SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a35d2fb980d187fc039bb378961d9464acf87a332f0037276efcb7e3d465911' 
  AND token = 'UBjX5U3UwDWHpAMhQC9lOqPGEAnerENpnoSzU7mWlck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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