SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff7cd4bba798b69cc999dbda823455da26359f1efb257555cce07bb956691042' 
  AND token = 'LLi9k1Dz/M2ZBfmjVaQ2TE/jRUT/ylm6AzUnU0L87fw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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