SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1cb11cdf3f80ff3b7854ff75e562573f35788a5b75a6b5922431231e03bcd7b' 
  AND token = 'FzIZlObCDnLtjLRnwEInHA60TfSDUdlGCHZjzeaKMTc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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