SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fe2b83949ed91e2be7fdfba2250ffe614138ba7e2202e109711ee7b12904120' 
  AND token = 'cgQtv+2N0EK1Kqnxws9MVjHOE+3eSUw2XutSLXQU2hU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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