SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f940d7af7ab96e89c07673458edcefbf033a935846171567047e1d95f1d43756' 
  AND token = 'Q0hxwGYmVTV3XaCYqdryGgeOts8wu2iEfyPVMqSzKK4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00102

JSON explain

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