SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c587836c48bb799af574db9ff24b709d948755826b897fa2463486187639da8d' 
  AND token = 'sMcux/uG+qaW9V3HPJQ4MzPRYO6/BbW1WOJ2bfrdYCg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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