SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '815469c02fd0e46e904988c3d249a70b2c5e87ed3265079f849e339b1509622d' 
  AND token = 'LsfR/lfZzqVbwaB1Yb9d1XTBV1T3pEVdbYvuN4oUtgI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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