SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd6b8f79ccb1d6d6b7b224f37f4d19c4f4f73059af704c3ef38753a511650cfe' 
  AND token = 'nUlc7y9iJ+upLPbSPS4zcFjfXIYLAcfPqkrOQLImBPs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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