SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '967392c44a23604989b3dfa9489e3b6cc55e68b4bcd6d124552c353ee1fe6bb2' 
  AND token = 'oqAq0fg/B75DzAkvE+LFBwn1s4xLLrxLwhTajBPbnww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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