SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de07041b12d17a603a32ef740fec5b929efafc241d10573e6357ce9c32d0e302' 
  AND token = 'osb/MzNVBMpdDXwd1V/JVGEXBtXyXV7NlUIR9rwF2f0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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