SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae54005ed2bfac474803a6e1fb739620a726478e622519887f8b67622def0fad' 
  AND token = 'I3t7WrpBS2DQXMPk/HR74/oTCt2FtUu+H0ngmC5ICMs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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