SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39e875357747e39ccce3714e6d6a96cfd7cc1fc68082e44bfe2d2e9d31287165' 
  AND token = 'RNIkKZ1cmQJOK4gPMryrHQaML4BobMYh0JX+MrYnBmM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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