SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6270f86762d2145267c01dea75a51ffa9a562850858010aac73a0153190824d7' 
  AND token = 'JS84UpsB7H3Ox1O2wxmBI59rpEmi9Jtq+YRQKUZyKPU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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