SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '117c8c9ba4ce2b534a2712aebffd260a15b9c845d368cb1f8bdd38b042f1aca5' 
  AND token = 't+V8fWxDEm8/Y8yHRXVBYkHwlqaqbDscmVjFnBMzC3c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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