SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3216cc26bae72f2a890d1ec9861c597b018a7b84209faa4428e8d074f8d7cd96' 
  AND token = 'KmV3JeeDoh7rIui6qKaFJPw3pEtOZAmBDWQq1/Fw3Xo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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