SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f3a5d204216712f7308fcf230f1690e6a49ab3597a6cc884ebb78d6b1a64011' 
  AND token = '/UXZC5Li2aiLw2A8dLooHojSmYsQBuFQm+nANTijvpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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