SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bdaab6dd6c277129e014bdbec177bd2ab0e437211eb1831fccbfc592c5d3646' 
  AND token = 'v3j134/u8Lp12DCIYrlJUSMXpK5sSc/UwQMmTuFMo/c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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