SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db4fe3ee0a01c2706fe2504aab9186a987bb5df67289f25648271075fc6221d3' 
  AND token = 'nDaxHHK/1Te7noiZ5FHsstIzIG4kf/frDbRexcqwhLk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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