SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '633dc04eddf82ad351f387861169c8c5294e6fd76ed062e2081bf04daa7d4fe1' 
  AND token = 'GaBcYHjtb4gUjspOe7Z+fdmz5nnpzqffzgn/9xOQLJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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