SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c167b0f139affa324c9d7cdd2935a7f1ed122cab0ed20a46e37fad8b808f11c7' 
  AND token = 'djzvIwY+1ZwmMGNPYVBCG2LwWNnMuMgdPHc5BeAuKNc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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