SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '88a1b5ed2f5f823136b078bfcd438d36cd4ed53d78ad458b81f9725187bf3785' 
  AND token = 'isCO2bhHZwrPNNQkCfuOA/rhKlmxCYHJ0PLtrDOplgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}