SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd20745993fbf6c482946c56853143f3458b775db83b503594df5a6e0c16626d6' 
  AND token = 'BKRvFpVOs+cnFOBUnHYxM45LrmwciQIZahmHXPg3/E8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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