SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '96ef56ab8b9d5afd100b3112e2117d9b28179cd1ed6f967c226740ff49593739' 
  AND token = '46DVktpHixHnT/kzE2qwW4B436EF37bCERlKZaVQMlg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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