SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e64cbe372e57905fe06294284bb0aa392b9142cf03be186668eb886923a95dfa' 
  AND token = '6j84ZbkkqSaYQI4T3vZ0jTDdWdhWMwB6gZZs3oyWCHA=' 
  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"
    }
  }
}