SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e5071d4b4c6c9c52f390409cf4230d937b6bb74dc649e24a92bd7c5c1987ee14' 
  AND token = 'xm2FoQ999gP3vgWvE2lJo7uHlKFvDGKDzhr0YUaDSNA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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