SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bb7cbd9cfac11574be0b2470d29d7fd710507dd90227f71cfbfadd468f7a651' 
  AND token = 'koZaDi1tGKV27hUEC//j5Tysyot/6ToT4WTRxYJqBSo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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