SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb0014f40f0f1e4421d308254e0374cbfb3dc0505eff88528c1276301fa91118' 
  AND token = 'Xa15B60yuNLyaEGjOKLMDyuEFrwPxnG4pMpByfHkbL4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}