SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dbfbb9637c498ef2ca6463a2206a08fa1b414e7ca52505744e6bd1979ebd75b5' 
  AND token = 'UXeCpwqoUMpEPOAShUovyZIwwBTuwDVRsFg8ts//g5Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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