SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf82adf42eafa26dc640676667320ceb1a194afce97cc812a00ffbb34ee14c5f' 
  AND token = 'ufADJDRdO5RetsEFgKux5YHs06iasBUOsJm/JjnnRvk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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