SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04c616d9fbecf8297a05b364fb723be880acc2858fc24e711304154a03914b3c' 
  AND token = 'C+PrHykArp4hkzkv36wyodrY33zJb65X8yLLUYSXsOE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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