SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e19c8c5512801f4aabb5321278a3958a3a1576f08e89495f4d9a17e7a1414b2d' 
  AND token = 'B/Zvp/YoXK4zmgUG5vx2VGAyLxmE/jXJewqf8mD6q7s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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