SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df27999aae52e45b3e76005b7864b124d0149c795cbf3b87cdb6bb1087bda504' 
  AND token = 'f5SWYRgsIx/C/TqZMPKV/NQiJuWG61f+xJS/WRYuu+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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