SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3795902613d2a7fe2d587faede6dcfbc3b18d1819b6dbfdaca70678670819c5b' 
  AND token = 'FrWqurRqB4Z3unHRGrzjEMo2522IHPyCFZAAZlbyEI0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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