SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4dcfa38088b117ccc27d5f82c8f6b63dbb99680c100d14dd9559668b717f6057' 
  AND token = '5AoUABRwG2/tMBPWHDTuOuCihjrYbkoGlZMoeEgR9bI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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