SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3e484ee18dc765ea1f03a6462b058474253cb9447d9d228d740f32f7739bb2b' 
  AND token = '+uySorDGRBmM4wrJc/nTwwvcJWXK1epZEL7g36iPAis=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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