SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf7dc43dfcec67e825bba7bed0648306cfddba6379e43cbdfb151d9746561f76' 
  AND token = '8EmygcmP+8NXBuOLXPGoG+cFxO8MVapTLX8TDk10heg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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