SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e83781afac5ce2959f6575efe8a45c38c4209e7e70d9b79172f4e8b0208b878' 
  AND token = 'TkevrhSyJnVOlLxcmEDxqqItJHnIFXpDprHswNLfGK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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