SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '447ff6f77800b6d49f5292da8558e9790e3d3078d45aa92b6084368b55546387' 
  AND token = 'yJFDyqVvgEvmGiy9WoBV0vzZmXQTTetCeRzPlvnWN2Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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