SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1a750dc27c0a1b5f426384d8a764d8ec3e9814930a2b22a47964fabb681ff2d' 
  AND token = 'PCByZRYr8u8CsFWQmBSyTDMZiRRyMvds+tUAKIJKWpk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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