SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '59e86bc50cf417425fed3d18027305345c3e443894cf633d110997daf8b52d12' 
  AND token = 'R99BG5y/3vaJvU0ZzQNgl0f0sPVrO6viQgPG3GbSZu0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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