SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af1bd266f5efaccdd5ee466ac8074c6dbb98cea4a5365690e4f5fd3356148cac' 
  AND token = 'hRL1A0eXXdIlsZeOMahLExJVcgth2A9xkKlqO5lmmMA=' 
  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"
    }
  }
}