SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a49222238d2bca96d49a13fb5f869e7b482bdef161011622863da424d6b99be5' 
  AND token = 'txCk5P0C1a0hNRBn69bqG7ckd7pONvL9tdwFx3MV9H4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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