SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f20a9e2348fb391c9bb3ab65eb89681bf55b8e044c48b7a26dad3bec8070fd0a' 
  AND token = 'gyL+2C2dvCvrfbYP5vpkXwDJhIW1I/KTNW0Kvpgh6Oo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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